1. Technical Field
The present invention relates to a compression device, in particular a compression device for artificial valve replacing device.
2. Description of Related Art
When the patient's own heart valves can not open or close normally because of the variation caused by the congenital or acquired disease, the patient's health and even life will be affected. Variations of heart valves are divided into insufficient opening and insufficient closing, both of which may create greater load on heart. Whether the heart can work regularly under this load determines the replacement of the heart valve for the human. If the heart valve has to be replaced for the patient, the existing method is to carry out the valve replacement surgery, which means the surgeon performs the thoracotomy for the patient to stop the heart and connects the patient onto the cardiopulmonary circulatory system in vitro. The surgeon then cuts off the diseased heart valve, sews the artificial replacement valve on the very place, and finally sutures the heart and the chest. This is a quite traumatic surgical procedure, involving certain risk of death and a long time to recover. Due to the surgical trauma, many patients can not afford it or undergo the surgery even though they are in need of replacement of heart valves.
To lower the risk of surgery. U.S. Pat. No. 5,370,685, U.S. Pat. No. 5,411,552, U.S. Pat. No. 5,718,725 and U.S. Pat. No. 6,425,916 discloses the method for non-thoracic surgery for replacing heart valve and the artificial heart valve replacement device that can reduce the trauma and pain caused by thoracotomy. The artificial valve replacement device comprises the nickel-titanium shape-memory alloy stent directed into the body vascular cavity by means of catheter tube insertion technology. Before entering human body, the stent has to be compressed and placed into the transport sheath catheter so as to adapt to the vessel diameter and avoid scratching the vascular wall.
In the patent entitled “Prosthetic Valve Crimping Device” with Chinese patent authorization notice number of CN101257863 dated May 11, 2011, a crimping mechanism is disclosed, whereby a plurality of circumferentially arrayed wedge-shaped blocks form an equilateral polygon and peripheral closed columnar space. The compression and expansion of the equilateral polygon columnar space is achieved through each wedge-shaped block's synchronous and translational moving to the axis center. The design requires the slide and the driving structure added to the periphery of the wedge-shaped blocks to ensure its translational and synchronous movement plus the base part.
The device has high manufacturing cost and complicated structure, bringing difficulties to cleaning and sterilization; and therefore is required for disposable use, which undoubtedly creates great burden to patients. Moreover, the device has larger outside dimension, making it impossible to do martensitic transformation treatment on the nickel-titanium shape-memory alloy stent with simple cooling method (such as a flat pan filled with ice-water mixture). If the stent is compressed after becoming soft at a low temperature, such as being compressed under austenite phase, it will produce multiple radial supporting forces, causing loading problems and easy damage to the sheath catheter.